Yes, he could be with the Sox until the end of the season. Players get claimed off waivers all the time, most of the time deals are not made.

Sometimes a team will put in a claim to block another team from getting the player (this is how we think Rios ended up with us. The theory was that Kenny wanted to block the Tigers from getting him). If a deal is not worked out in 48 hours, the player stays. The Sox can pull him back even before the 48 hours expire.